Mold for a V-groove fiber array base block and fabrication method thereof

ABSTRACT

A V-groove mold fabrication method is disclosed. The method for fabricating a V-groove mold includes the following steps: (a) providing a matrix substrate having a plurality of V-grooves, and then forming a metal layer on said matrix substrate; immersing said matrix substrate having said metal layer thereon with an electroforming metal ion solution and forming a father mold by an electroforming process; and separating said father mold from said matrix substrate.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for fabricating aV-groove mold and, more particularly, to a method for fabricating a moldfor further mass-producing V-groove fiber array base blocks.

[0003] 2. Description of Related Art

[0004] Owing to the booming high-volume communication through opticalfibers, the fiber array modules are in great demand now. Basically, thefiber array modules are made by bonding optical fibers on base blockshaving a plurality of grooves. For meeting the great demand for fiberarray modules, improvements for mass-producing base blocks have becomenecessary. Generally speaking, a base block used for fiber arraygenerally is a glass substrate or a silicone substrate having V-grooves.Traditionally, these substrates for base blocks are made by forminggrooves through cutting or carving by knives. However, this traditionalmethod for making base blocks not only takes a long time but alsoresults in damage on the substrate. Moreover, the process for carvinggrooves is complex and is not suitable for mass production.Alternatively, photolithography is suggested for forming V-shapedgrooves on the substrate of base blocks. However, only a siliconsubstrate for a fiber array module can be processed. It is difficult tomanufacture the glass substrate having V-grooves throughphotolithography. Recently, new glass and plastic materials used formanufacturing fiber array base block by injection moldings or pressmoldings have been reported. Nevertheless, a method for efficientlyfabricating a suitable mold for the fiber array base block is still notfound. Furthermore, fabricating a mold for a fiber array base blockalways involves a huge amount of time and this inevitably makes theexisting fiber array base blocks uneconomic. There is a need forimprovement of the fabrication process of the mold.

[0005] Therefore, it is desirable to provide a mold fabrication methodfor fiber array base blocks that eliminates the aforesaid drawback.

SUMMARY OF THE INVENTION

[0006] It is the main object of the present invention to provide afabrication method of a mold having V-grooves for simplifying themass-production of said molds and shortening the time involved forfabricating said molds.

[0007] Another object of the present invention is to provide a V-groovemold, which can be used in fabricating a substrate of a fiber array baseblock by injection moldings or press moldings.

[0008] To achieve these and other objects of the present invention, themethod for fabricating a mold for fiber array base blocks comprises thesteps of: providing a matrix substrate having a plurality of V-grooves,and then forming a metal layer on said substrate; immersing said matrixsubstrate having said metal layer formed thereon with an electroformingmetal ion solution and forming a father mold by an electroformingprocess; and separating said father mold from said matrix substrate. Themetal of the metal layer is unlimited. Preferably, the metal of themetal layer is selected from the group consisting of copper, nickel,silver, gold, and alloys thereof. More preferably, the metal of themetal layer is copper, silver, or alloys thereof. Preferably, theelectroforming metal of the father mold of present invention is selectedfrom the group consisting of nickel, nickel-containing alloys, silver,copper, gold, chromium, and aluminum. Most preferably, thenickel-containing electroforming metal of the father mold is nickel-ironalloy, nickel-cobalt alloy, nickel-tungsten alloy, nickel-manganesealloy, Ni—SiC (nickel-siliconcarbide alloy), or Ni—Fe—TiO₂ alloy.

[0009] The fabrication method may selectively further comprisefabricating a mother V-groove mold by the foregoing method. The methodof the present invention optionally further comprises the steps offorming a passive layer on the father mold surface; forming a mothermold on said passive layer by an electroforming process in anelectroforming metal ion solution; and separating said mother mold fromsaid father mold.

[0010] The present invention also relates to a V-groove mold having anelectroforming layer to a thickness between about 0.3 mm to about 30 mm.Preferably, the electroforming metal is selected from the groupconsisting of nickel, nickel-contained alloys, silver, copper, gold,chromium, and aluminum.

[0011] Other objects, advantages, and novel features of the inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a schematic drawing showing a process flow of oneembodiment for fabricating a V-groove mold of the present invention.

[0013]FIG. 2 is a schematic drawing showing a process flow of anotherembodiment for fabricating a V-groove mold of the present invention.

[0014]FIG. 3 is a schematic drawing showing a process flow of anotherembodiment for fabricating a V-groove mold of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] The present invention provides a mold for fabricating a V-groovefiber array base block and a mold fabrication method suitable for massproduction. The mold has an electroforming layer in a V-groove shape.The material of metal layer is unlimited. Preferably, the metal of themetal layer is selected from the group consisting of copper, nickel,silver, gold, and alloys thereof. More preferably, the metal of themetal layer is copper, silver, or alloys thereof formed by evaporationor sputtering. The metal layer is in order to make the matrix substratemore conductive for conducting further electroforming. Preferably, theelectroforming metal of the mold of present invention is selected fromthe group consisting of nickel, nickel-contained alloys, silver, copper,gold, chromium, and aluminum. More preferably, the nickel-containingelectroforming metal of the mold is nickel-iron alloy, nickel-cobaltalloy, nickel-tungsten alloy, nickel-manganese alloy, Ni—SiC, orNi—Fe—TiO₂ alloy. The thickness of the electroforming layer is notlimited. Preferably, the thickness of the electroforming layer rangesfrom 0.3 mm to about 30 mm.

[0016] The mold fabrication method comprises the steps of:

[0017] (A) providing a matrix substrate having a plurality of V-grooves,and then forming a metal layer on said matrix substrate;

[0018] (B) immersing said matrix substrate having said metal layerformed thereon with an electroforming metal ion solution and forming afather mold by an electroforming process; and

[0019] (C) separating said father mold from said matrix substrate.

[0020] The fabrication method may optionally further comprise thefollowing steps in order to improve throughput, if necessary.

[0021] (D) forming a passive layer on said father mold;

[0022] (E) forming a mother mold on said passive layer by anelectroforming process in an electroforming metal ion solution; and

[0023] (F) separating said mother mold from said father mold.

[0024] The passivation process in step (D) facilitates the release ofthe electroforming layer (the mother mold) from the V-groove father moldand further prevents the electroforming layer from combining with theV-groove father mold when proceeding in step (E). By repeating theprocess from step (D) to step (F), lots of mother molds can be produced.But the construction of the mother mold may not be equal to that of thefather mold. The fiber array base blocks can not be produced directly bythe mother mold so a son mold, constructed equal to the father mold formass-producing fiber array base blocks, is produced from the mother moldby passivation and electroforming processes. To be more specific, theson molds can be achieved through the following steps.

[0025] (G) forming a passive layer on said mother mold;

[0026] (H) forming a son mold on said passive layer by an electroformingprocess in an electroforming metal ion solution; and

[0027] (I) separating said son mold from said mother mold.

[0028] The son mold can be taken as a father mold for producing moremother molds from step (D) to step (F). A V-groove fiber array baseblock can be produced by either the son or father molds. The thicknessof the metal layer, preferably silver or copper, may be between about 40nm to about 200 nm. More preferably, the thickness of metal layer isbetween about 40 nm to about 80 nm. Preferably, the electroforming metalion solution is a nickel-containing solution. More preferably, thenickel-containing electroforming solution used to conduct theelectroforming process in steps (B), (E) and (H) is Ni(NH₂SO₃) 4H₂O orNiSO₄. The passivation process at steps (D) and (G) is exposing toplasma or immersing the mold surface with a passivation reagent. Thepassivation reagent is unlimited. Preferably, the passivation reagentcomprises a K₂Cr₂O₇ solution or a basic solution, such as Na₂CO₃ orNaOH, to form a passive layer by a chemical method. Optionally, thepassivation reagent may further include surfactant. Of course, thechemical method for forming a passive layer can be replaced by a plasmaprocess to form an oxide layer on the surface of the mold. The thicknessof the oxide layer is unlimited, but can not result in an adverse effecton the performance of the further electroforming process in steps (E) or(H). Preferably, the thickness of the oxide layer is particularly thinso that all the electroforming performances in steps (B), (E) and (H)are similar. The method of separating the electroformed mother mold fromthe father mold in step (F) is unlimited. The method of separating theelectroformed son mold from the mother mold in step (I) is alsounlimited. Preferably, the method in step (F) and (I) can be achieved byhand.

[0029] The application of the molds produced by the method of thepresent invention is not limited. Preferably, the V-groove mold of thepresent invention is applied for fabricating a fiber array base block byinjection moldings or press moldings, especially for a glass or plasticsubstrate.

[0030] The following embodiments of the present invention are examplesof a V-groove mold by using the fabrication method of the presentinvention.

EXAMPLE 1 Fabrication for a Single V-Groove Mold

[0031] With reference to FIG. 1, a process indicating the sequence forfabricating a V-groove mold of the present invention is shown. A siliconsubstrate 100 is used as a matrix substrate in the present embodiment. Asilver metal layer 110 is formed on the substrate 100 by sputtering. Thesputtering is achieved in a Denton Vacuum Desk II equipment under apressure of 75 mtorr and at an electric current of 45 mA. Then a silvermetal layer 110 of a thickness between about 40 nm to 80 nm is obtained.

[0032] In one aspect, the substrate 100 having the silver metal layer110 proceeds in an electroforming process. According to theelectroforming operating conditions in Table 1, a current densityranging from 2 ASD to 3 ASD is applied for 27 to 40 hours, and then thecurrent is increased to a range between about 12 ASD to about 14 ASD for8 days. A nickel-containing electroformed layer 120 of a thickness of 30mm is obtained. TABLE 1 Items Operating conditions Concentration ofNi(NH₂SO₃)4H₂O 450 g/L Concentration of NiCl₂6H₂O 6 g/L Concentration ofH₃BO₃ 40 g/L pH value 4.0 Temperature 50° C. Current density 1-10 ASDSurfactant 0.05-0.1 g/L Concentration of STAR FUTURON Stress relievingagent (STAR CS) 1-10 ml/L

[0033] The nickel-containing electroformed layer is then separated fromthe matrix substrate and taken as a V-groove father mold. There may besilicon residuals adhering to the father mold surface after moldseparation. Additional etching processes may be applied to remove boththe silicon residual and the metal layer on the father mold. The etchingsolution includes NH₄OH and H₂O₂. The V-groove profile on the surface ofthe father mold will be improved after the etching process.

EXAMPLE 2 Mass Production for V-Groove Molds

[0034] With reference to FIG. 2, a sequence of the manufacturing processfor mass-producing the mother molds of the present invention is shown.As shown in FIG. 2, a mother mold is obtained from the V-groove fathermold (i.e. nickel-containing electroformed layer) 120 fabricated inexample 1. A passive surface 125 is subsequently formed on the V-groovefather mold 120 by a passivation process. The passivation process isperformed by immersing the V-groove father mold 120 in a solution havinga passivation reagent such as a solution of Na₂CO₃ and a surfactant. Anoxide layer (i.e. a passive surface) 125 is formed on the surface of theV-groove father mold 120 by a chemical method. The operating conditionsfor the passivation process are shown in Table 2. TABLE 2 ItemsOperating conditions Concentration of 12.5 g/L Na₂CO₃ solutionTemperature 60° C. Type of cathode Titanium Mesh Area ratio of cathodeto anode 1:1 Current density for 1-3 ASD cathode and anode Reaction time0.2-1 mins

[0035] When the V-groove father mold 120 is exposed to the passivesolution, the cathode of the power supply is connected to the V-groovefather mold 120 and the anode is connected to a titanium mesh. Adegreasing process is executed for 30 seconds at the current equal to 2ASD. By exchanging the location of the V-groove father mold 120 withthat of titanium mesh, (i.e. connecting the anode of the power supply tothe V-groove father mold 120 and connecting the cathode to the titaniummesh), the passivation process is achieved after being conducted for 30seconds at the current equal to 2 ASD.

[0036] By repeating the electroforming process described in example 1, anickel-containing electroformed layer (i.e. a mother mold) 140 is formedon the passive surface 125. The passive layer is then separated orreleased from the V-groove father mold.

[0037] With reference to FIG. 3, a sequence of the manufacturing processfor mass-producing the father molds of the present invention is shown.As shown in FIG. 3, a son mold 150 is obtained from the V-groove mothermold 140. A passive surface 145 is subsequently formed on the V-groovemother mold 140 by a passivation process. The passivation process isperformed by immersing the V-groove mother mold 140 in a solution havinga passivation reagent such as a solution of Na₂CO₃ and a surfactant. Anoxide layer (i.e. a passive surface) 145 is formed on the surface of theV-groove mother mold 140 by a chemical method. The operating conditionsfor the passivation process are same as those shown in Table 2.

[0038] By repeating the electroforming process described in example 1, anickel-containing electroformed layer (i.e. a son mold) 150 is formed onthe passive surface 145. The passive layer is then separated or releasedfrom the V-groove mother mold 140. The son mold 150 can be taken asanother nickel-containing father mold for further application ofmass-production. According to this method, every nickel-containing metalmold can be treated as a mold to duplicate another mold.

EXAMPLE 3 Fabrication for a Single V-Groove Mold

[0039] With reference to FIG. 1, a process indicating the sequence forfabricating a V-groove mold of the present invention is shown. A PyrexSubstrate (i.e. a glass substrate) 100 is used as a matrix substrate inthe present embodiment. A nickel metal layer 110 is formed on thesubstrate 100 by sputtering. The sputtering is achieved in a DentonVacuum Desk II equipment under a pressure of 75 mtorr and at an electriccurrent of 45 mA. Then a nickel metal layer 110 of a thickness betweenabout 0.04 μm to 0.08 μm is obtained.

[0040] In one aspect, the substrate 100 having the nickel metal layer110 proceeds in an electroforming process. According to theelectroforming operating conditions in Table 3, a current density rangesfrom 2 ASD to 3 ASD is applied for 27 to 40 hours, and then the currentis increased to a range between about 12 ASD to about 14 ASD for 8 days.A nickel-containing (a nickel-iron alloy) electroformed layer 120 of athickness of 30 mm is obtained. TABLE 3 Items Operating conditionsConcentration of Ni(SO₄) 6H₂O 200 g/L Concentration of Fe₂(SO₄)₃ 8 g/LConcentration of H₃BO₃ 25 g/L Concentration of FeCl₃ 5 g/L Saccharin 3g/L pH value 2.8-4.2 Temperature 50-65° C. Current density 0.1-8 ASDSurfactant 5 ml/L Surface tension 27 mN/m

[0041] The nickel-containing electroformed layer is then separated fromthe matrix substrate and taken as a V-groove father mold.

EXAMPLE 4 Mass Production for V-Groove Molds

[0042] With reference to FIG. 2, a sequence of the manufacturing processfor mass-producing the mother molds of the present invention is shown.As shown in FIG. 2, a mother mold is obtained from the V-groove fathermold (i.e. nickel-containing electroformed layer) 120 fabricated inexample 3. A passive surface 125 is subsequently formed on the V-groovefather mold 120 by a passivation process. The passivation process isperformed by immersing the V-groove father mold 120 in a solution havinga passivation reagent such as a solution of K₂Cr₂O₇ and a surfactant. Anoxide layer (i.e. a passive surface) 125 is formed on the surface of theV-groove father mold 120 by a chemical method. The operating conditionsfor the passivation process are shown in Table 4. TABLE 4 ItemsOperating conditions Concentration of 0.6 g/L K₂Cr₂O₇ solutionConcentration of a passivation 50 ml/L reagent for Nickel-iron alloyTemperature 25-40° C. Type of cathode Titanium Mesh Area ratio ofcathode to anode 1:1 Current density for 1-5 ASD cathode and anodeReaction time 0.2-1 mins

[0043] When the V-groove father mold 120 is exposed to the passivesolution, the cathode of the power supply is connected to the V-groovefather mold 120 and the anode is connected to a titanium mesh. Adegreasing process is executed for 30 seconds at the current equal to 2ASD. By exchanging the location of the V-groove father mold 120 withthat of titanium mesh, (i.e. connecting the anode of power supply to thesecond V-groove mold 120 and connecting the cathode to the titaniummesh), the passivation process is achieved after being conducted for 30seconds at the current equal to 2 ASD.

[0044] By repeating the electroforming process described in example 3, anickel-containing (a nickel-iron alloy) electroformed layer (i.e. amother mold) 140 is formed on the passive surface 125. The passive layeris then separated or released from the V-groove father mold. Thenickel-containing electroformed layer (i.e. a mother mold) 140 can betaken as another nickel-containing mold for further application ofmass-production by repeating the passivation process and electroformingprocess described above. According to this method, everynickel-containing metal mold can be treated as a mold to duplicateanother mold.

[0045] The present invention provides a V-groove mold, which is used infabricating a glass substrate or a silicon substrate of a fiber arraybase block through injection moldings or press moldings. Meanwhile, thepresent invention also provides a novel method for duplicating thisV-groove mold rapidly by passivation process. In other words, thefabrication method facilitates the mass production of the glasssubstrates and silicon substrate by simplifying the duplication ofplural copies of the same molds used for injecting molding (or pressmolding) in a short period.

[0046] Although the present invention has been explained in relation toits preferred embodiments, it is to be understood that many otherpossible modifications and variations can be made without departing fromthe spirit and scope of the invention as hereinafter claimed.

What is claimed is:
 1. A method for fabricating a mold for a fiber arraybase block comprising the steps of: (a) providing a matrix substratehaving a plurality of V-grooves, and then forming a metal layer on saidmatrix substrate; (b) immersing said matrix substrate having said metallayer thereon with an electroforming metal ion solution and forming afather mold by an electroforming process; and (c) separating said fathermold from said matrix substrate.
 2. The method as claimed in claim 1,further comprising: (d) forming a passive layer on said father mold; (e)forming a mother mold on said passive layer by an electroforming processin an electroforming metal ion solution; and (f) separating said mothermold from said father mold.
 3. The method as claimed in claim 2, furthercomprising: (g) forming a passive layer on said mother mold; (h) forminga son mold on said passive layer by an electroforming process in anelectroforming metal ion solution; and (i) separating said son mold fromsaid mother mold; wherein said son mold is taken as a father mold formass-production.
 4. The method as claimed in claim 1, wherein thematerial of said metal layer is selected from the group consisting ofcopper, nickel, silver, gold, and alloys thereof.
 5. The method asclaimed in claim 1, wherein said metal of said mold formed by saidelectroforming process is selected from the group consisting of nickel,nickel-containing alloys, silver, copper, gold, chromium, and aluminum.6. The method as claimed in claim 2, wherein said metal of said moldformed by said electroforming process is selected from the groupconsisting of nickel, nickel-containing alloys, silver, copper, gold,chromium, and aluminum.
 7. The method as claimed in claim 3, whereinsaid metal of said mold formed by said electroforming process isselected from the group consisting of nickel, nickel-containing alloys,silver, copper, gold, chromium, and aluminum.
 8. The method as claimedin claim 5, wherein said nickel-containing alloys comprise nickel-ironalloy, nickel-cobalt alloy, nickel-tungsten alloy, nickel-manganesealloy, Ni—SiC, or Ni—Fe—TiO₂ alloy.
 9. The method as claimed in claim 6,wherein said nickel-containing alloys comprise nickel-iron alloy,nickel-cobalt alloy, nickel-tungsten alloy, nickel-manganese alloy,Ni—SiC, or Ni—Fe—TiO₂ alloy.
 10. The method as claimed in claim 7,wherein said nickel-containing alloys comprise nickel-iron alloy,nickel-cobalt alloy, nickel-tungsten alloy, nickel-manganese alloy,Ni—SiC, or Ni—Fe—TiO₂ alloy.
 11. The method as claimed in claim 1,wherein said electroforming metal ion solution used for electroformingin step (b) is a solution of Ni(NH₂SO₃) 4H₂O or NiSO₄.
 12. The method asclaimed in claim 2, wherein said passive layer is formed by exposingsaid surface of said father mold to plasma, a K₂Cr₂O₇ solution or abasic solution.
 13. The method as claimed in claim 12, wherein saidbasic solution is Na₂CO₃ or NaOH.
 14. The method as claimed in claim 3,wherein said father mold or son mold is applied for injection moldingfiber array base blocks.
 15. The method as claimed in claim 3, whereinsaid father mold or son mold is applied for press molding fiber arraybase blocks.
 16. The method as claimed in claim 1, wherein the thicknessof said metal layer ranges from 0.04 μm to 0.2 μm.
 17. The method asclaimed in claim 2, wherein said passive layer is a metal oxide layer.18. The method as claimed in claim 1, wherein sputtering or evaporationforms said metal layer.
 19. The method as claimed in claim 1, furthercomprising step (c1) etching said metal layer remaining on said fathermold using H₂O₂ and NH₄OH after step (c).